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STM32F10xxx USART application examples

Application Note

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Last Updated: 27/06/2007

Pages: 23

Related Datasheets

Low-density access line, ARM-based 32-bit MCU with 16 or 32 KB Flash, 5 timers, ADC and 4 communication interfaces

Low-density performance line, ARM-based 32-bit MCU with 16 or 32 KB Flash, USB, CAN, 6 timers, 2 ADCs, 6 communication interfaces

Medium-density access line, ARM-based 32-bit MCU with 64 or 128 KB Flash, 6 timers, ADC and 7 communication interfaces

Medium-density performance line ARM-based 32-bit MCU with 64 or 128 KB Flash, USB, CAN, 7 timers, 2 ADCs, 9 communication interfaces

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AN2582 Application note
STM32F10xxx USART application examples
Introduction
This application note is intended to provide practical application examples of the STM32F10xxx USART peripheral use. This document, its associated firmware, and other such application notes are written to accompany the STM32F10xxx firmware library. These are available for download from the STMicroelectronics website: www.st.com.

June 2007

Rev 1

1/23
www.st.com

Contents

AN2582 - Application note

Contents
1 STM32F10xxx USART hardware flow control communication . . . . . . . 5
1.1 1.2 1.3 1.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 C onclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2

STM32F10xxx USART interrupt communication with HyperTerminal . 6
2.1 2.2 2.3 2.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 C onclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3

STM32F10xxx USART-USART communication using flags . . . . . . . . . . 7
3.1 3.2 3.3 3.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 C onclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

4

STM32F10xxx USART-USART communication using interrupts . . . . . 8
4.1 4.2 4.3 4.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 C onclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

5

STM32F10xxx USART-USART communication using DMA . . . . . . . . . . 9
5.1 5.2 5.3 5.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 C onclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

6

USART-USART communication using DMA, flags and interrupts . . . 10
6.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2/23

AN2582 - Application note

Contents

6.2 6.3 6.4

Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

7

STM32F10xxx USART retargeting of C printf function . . . . . . . . . . . . 12
7.1 7.2 7.3 7.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

8

STM32F10xxx USART synchronous mode (SPI mode) . . . . . . . . . . . . 13
8.1 8.2 8.3 8.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

9

STM32F10xxx USART half-duplex mode . . . . . . . . . . . . . . . . . . . . . . . 14
9.1 9.2 9.3 9.4 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

10

STM32F10xxx USART IrDA mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1 STM32F10xxx USART IrDA Transmit mode . . . . . . . . . . . . . . . . . . . . . . 15
10.1.1 10.1.2 10.1.3 10.1.4 Over view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

10.2

STM32F10xxx USART IrDA Receive mode . . . . . . . . . . . . . . . . . . . . . . . 17
10.2.1 10.2.2 10.2.3 10.2.4 Over view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

11

STM32F10xxx USART multiprocessor communication . . . . . . . . . . . . 18
11.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3/23

Contents

AN2582 - Application note

11.2 11.3 11.4

Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

12

STM32F10x USART Smartcard mode . . . . . . . . . . . . . . . . . . . . . . . . . . 20
12.1 12.2 12.3 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Hardware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Firmware description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

13

Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

4/23

AN2582 - Application note

STM32F10xxx USART hardware flow control communication

1

STM32F10xxx USART hardware flow control communication
Overview
This section provides a description of how to use the USART with hardware flow control (RTS, CTS), and communicate with the HyperTerminal.

1.1

1.2

Hardware description
Figure 1 shows a typical interface between the STM32F10xxx USART and the PC HyperTerminal. All USART2 signals (Rx, Tx, RTS and CTS) must be connected to a DB9 connector using an RS232 transceiver. Moreover, a null-modem female/female RS232 cable is connected between the DB9 connector (CN5 on STM3210B-EVAL board) and the PC serial port. Figure 1. STM32F10xxx USART and HyperTerminal interface

USART2_TX USART2_RX USART2_CTS USART2_RTS

USART transceiver

DB9 connector

to PC HyperTerminal

STM32F10xxx

ai14347

1.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, USART2 sends a predefined buffer to the HyperTerminal and waits for a string from the HyperTerminal. The string is entered by the user and must end with the \r character (keypad ENTER button). It is stored into the receive buffer array. The maximum receive buffer size is defined in bytes in the RxBufferSize variable and can be configured by the user. Each received byte is retransmitted to the HyperTerminal. This firmware is provided as USART example 1 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

1.4

Conclusion
The STM32F10xxx USART has a modem function (CTS and RTS) that improves the application security regarding data transfers, and requires less software to control the data flow.

5/23

STM32F10xxx USART interrupt communication with HyperTerminal

AN2582 - Application note

2

STM32F10xxx USART interrupt communication with HyperTerminal
Overview
This section provides a description of how to use the USART interrupts to communicate with the HyperTerminal.

2.1

2.2

Hardware description
Figure 2 shows a typical interface between the STM32F10xxx USART and the PC HyperTerminal. The USART1 signals (Rx, Tx) must be connected to a DB9 connector using an RS232 transceiver. Moreover, a null-modem female/female RS232 cable is connected between the DB9 connector (CN6 on STM3210B-EVAL board) and the PC serial port. Figure 2. STM32F10xxx USART and HyperTerminal interface

USART1_TX USART1_RX

USART transceiver

DB9 connector

to PC HyperTerminal

STM32F10xxx

ai14348

2.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, USART1 sends a predefined buffer to the HyperTerminal and waits for a string from the HyperTerminal. The string length is defined by the user-configurable RxBufferSize variable. The communication is managed by Transmit and Receive interrupts. The userentered string is stored into the receive buffer array. The receive buffer has a maximum size of RxBufferSize bytes. This firmware is provided as USART example 2 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

2.4

Conclusion
The STM32F10xxx USART interrupts provide a greater flexibility when sending and receiving data. Communication with the HyperTerminal was used for the demonstration purpose.

6/23

AN2582 - Application note

STM32F10xxx USART-USART communication using flags

3

STM32F10xxx USART-USART communication using flags
Overview
This section describes how to build a basic communication between USART1 and USART2 using flags.

3.1

3.2

Hardware description
Figure 3 shows a typical interface between the STM32F10xxx USART1 and USART2. The USART1 signals (Rx, Tx) must be connected to a DB9 connector using an RS232 transceiver and the same connection must be done for the USART2 signals. Moreover, a null-modem female/female RS232 cable is connected between the two DB9 connectors (CN6 and CN5 on STM3210B-EVAL board). Figure 3. STM32F10xxx USART-USART interface
USART1_TX USART1_RX USART2_TX USART2_RX

USART transceiver

DB9 connector

USART transceiver

DB9 connector

STM32F10xxx

ai14349

3.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, USART1 sends a predefined buffer to USART2. USART2 reads the received data and stores it into its receive buffer. The received data are then compared with the sent data and the result of this comparison is stored into the TransferStatus variable. This firmware is provided as USART example 3 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

3.4

Conclusion
The STM32F10xxx USART flags can easily be used to control a communication between two USARTs.

7/23

STM32F10xxx USART-USART communication using interrupts

AN2582 - Application note

4

STM32F10xxx USART-USART communication using interrupts
Overview
This section describes how to build a basic communication between USART1 and USART2 using interrupts.

4.1

4.2

Hardware description
Figure 4 shows a typical interface between the STM32F10xxx USART1 and USART2. The USART1 signals (Rx, Tx) must be connected to a DB9 connector using an RS232 transceiver and the same connection must be done for the USART2 signals. Moreover, a null-modem female/female RS232 cable is connected between the two DB9 connectors (CN6 and CN5 on STM3210B-EVAL board). Figure 4. STM32F10xxx USART-USART interface

USART1_TX USART1_RX USART2_TX USART2_RX

USART transceiver

DB9 connector

USART transceiver

DB9 connector

STM32F10xxx

ai14349

4.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, two predefined buffers are sent, one from USART1 to USART2 and the other, from USART2 to USART1. The received data are stored into the USART2 and USART1 receive buffers, respectively. The data transfers are managed in the stm32f10x.c files in the USART1 and USART2 interrupt service routines. The sent and the received data buffers are then compared. This firmware is provided as USART example 4 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

4.4

Conclusion
The use of USART interrupts within a communication further reduces the code density and makes it easy to transmit and receive data.

8/23

AN2582 - Application note

STM32F10xxx USART-USART communication using DMA

5

STM32F10xxx USART-USART communication using DMA
Overview
This section describes how to build a basic communication between USART1 and USART2 using the DMA capability.

5.1

5.2

Hardware description
Figure 5 shows a typical interface between the STM32F10xxx USART1 and USART2. The USART1 signals (Rx, Tx) must be connected to a DB9 connector using an RS232 transceiver and the same connection must be done for the USART2 signals. Moreover, a null-modem female/female RS232 cable is connected between the two DB9 connectors (CN6 and CN5 on STM3210B-EVAL board). Figure 5. STM32F10xxx USART-USART interface
USART1_TX USART1_RX USART2_TX USART2_RX

USART transceiver

DB9 connector

USART transceiver

DB9 connector

STM32F10xxx

ai14349

5.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, DMA is used to transfer data from a predefined transmit buffer to the USART2 Transmit data register, then the data are sent to USART1. The data received by USART1 are transferred by DMA and stored into a predefined receive buffer, then compared with the sent data and the result of the comparison is stored into the TransferStatus1 variable. Then, DMA is used to transfer data from a predefined transmit buffer to the USART1 Transmit data register, then the data are sent to USART2. The data received by USART2 are transferred by DMA and stored into a predefined receive buffer, then compared with the sent data and the result of the comparison is stored into the TransferStatus2 variable. This firmware is provided as USART example 5 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

5.4

Conclusion
The use of DMA within a communication further reduces the code density and execution time. It is also easier to transmit and receive data.

9/23

USART-USART communication using DMA, flags and interrupts

AN2582 - Application note

6

USART-USART communication using DMA, flags and interrupts
Overview
This section describes how to build a basic communication between USART1 and USART2 using DMA, flags and interrupts.

6.1

6.2

Hardware description
Figure 6 shows a typical interface between the STM32F10xxx USART1 and USART2. The USART1 signals (Rx, Tx) must be connected to a DB9 connector using an RS232 transceiver and the same connection must be done for the USART2 signals. Moreover, a null-modem female/female RS232 cable is connected between the two DB9 connectors (CN6 and CN5 on STM3210B-EVAL board). Figure 6. STM32F10xxx USART-USART interface

USART1_TX USART1_RX USART2_TX USART2_RX

USART transceiver

DB9 connector

USART transceiver

DB9 connector

STM32F10xxx

ai14349

6.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, DMA is used to transfer data from a predefined transmit buffer to the USART2 Transmit data register, then the data are sent to USART1. The data received by USART1 are transferred using the RxNE flag, and stored into a predefined receive buffer. They are then compared with the sent data and the result of this comparison is stored into the TransferStatus1 variable. Then, DMA is used to transfer data from a predefined transmit buffer to the USART1 Transmit data register, then the data are sent to USART2. The data received by USART2 are transferred using the Receive interrupt, and stored into a predefined receive buffer. They are then compared with the sent data and the result of this comparison is stored into the TransferStatus2 variable. This firmware is provided as USART example 6 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

10/23

AN2582 - Application note

USART-USART communication using DMA, flags and interrupts

6.4

Conclusion
In multibuffer communication, the STM32F10xxx USART triggers DMA on send/receive requests that can be used for data transfer. This leaves the CPU free to perform other tasks.

11/23

STM32F10xxx USART retargeting of C printf function

AN2582 - Application note

7
7.1

STM32F10xxx USART retargeting of C printf function
Overview
This section shows how use the USART to retarget the C library printf function.

7.2

Hardware description
Figure 7 shows a typical interface between the STM32F10xxx USART and the PC HyperTerminal. The USART1 signals (Rx, Tx) must be connected to a DB9 connector using an RS232 transceiver. Moreover, a null-modem female/female RS232 cable is connected between the DB9 connector (CN6 on STM3210B-EVAL board) and the PC serial port. Figure 7. STM32F10xxx USART and HyperTerminal interface

USART1_TX USART1_RX

USART transceiver

DB9 connector

to PC HyperTerminal

STM32F10xxx

ai14348

7.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. This implementation outputs the printf message on the HyperTerminal using USARTx. USARTx can be USART1, USART2 or USART3; to select the USART interface to be used uncomment the #define USE_USARTx line in the main.h file. This firmware is provided as USART example 7 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

7.4

Conclusion
The STM32F10xxx USART can be used to retarget the C printf function. The user can display the message on the HyperTerminal.

12/23

AN2582 - Application note

STM32F10xxx USART synchronous mode (SPI mode)

8
8.1

STM32F10xxx USART synchronous mode (SPI mode)
Overview
This section describes how to build a basic communication between USART1 (Synchronous mode) and SPI1 using flags.

8.2

Hardware description
Figure 8 shows a typical interface between the STM32F10xxx USART1 and SPI1. USART1_Tx (PA9) is connected to SPI1_MOSI (PA7), USART1_Rx (PA10) is connected to SPI1_MISO (PA6) and USART1_CK (PA8) is connected to SPI1_SCK(PA5). Figure 8. STM32F10xxx USART-SPI interface
SPI1_MOSI SPI1_MISO SPI1_SCK

USART1_CK USART1_Rx USART1_Tx

STM32F10xxx

ai14350

8.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, USART1 sends data from a predefined transmit buffer to SPI1 using the TxE flag. The data, received by SPI1 using the RxNE flag, are stored into a predefined receive buffer, then compared with the sent data and the result of the comparison is stored into the TransferStatus1 variable. Then, SPI1 sends data from a predefined transmit buffer to USART1 using the TxE flag. The data received by USART1 using the RxNE flag, is stored into a predefined receive buffer, then compared with the sent data and the result of the comparison is stored into the TransferStatus2 variable. This firmware is provided as USART example 8 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

8.4

Conclusion
In synchronous mode, with its clock output, the STM32F10xxx USART can communicate with an SPI interface. The USART can only be the master.

13/23

STM32F10xxx USART half-duplex mode

AN2582 - Application note

9
9.1

STM32F10xxx USART half-duplex mode
Overview
This section describes how to build a basic communication between USART1 and USART2 in half-duplex mode using flags.

9.2

Hardware description
Figure 9 shows a typical interface between the STM32F10xxx USART1 and USART2 in half-duplex mode. USART1_Tx (PA9) is connected to USART2_Tx (PD5) and a pull-up resistor is connected to the line (10 k). Figure 9. STM32F10xxx USART-USART half-duplex interface

USART1_Tx

10 k 3.3 V

USART2_Tx

STM32F10xxx

ai14359

9.3

Firmware description
The provided firmware includes the USART driver the supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, USART1 sends data from a predefined transmit buffer to USART2 using the TxE flag. The data received by USART2 using RxNE flag, is stored into a predefined receive buffer, then compared with the sent data, and the result of the comparison is stored into the TransferStatus1 variable. Then, USART2 sends data from a predefined transmit buffer to USART1 using the TxE flag. The data received by USART1 using the RxNE flag is stored into a predefined receive buffer, then compared with the sent data and the result of this comparison is stored into the TransferStatus2 variable. This firmware is provided as USART example 9 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

9.4

Conclusion
The STM32F10xxx USART can communicate in half-duplex mode. In this mode, the USARTx_Rx pin is no longer used.

14/23

AN2582 - Application note

STM32F10xxx USART IrDA mode

10

STM32F10xxx USART IrDA mode
The example 10 provides two IrDA programs: transmitter & receiver. To run the full demonstration, two boards are required:

one board to act as the IrDA transmitter one board to act as the IrDA receiver

10.1
10.1.1

STM32F10xxx USART IrDA Transmit mode
Overview
This section describes how to build a basic communication with USART3 in IrDA transmit mode.

10.1.2

Hardware description
Figure 10 shows the STM32F10xxx IrDA interface. Figure 10. STM32F10xxx USART IrDA interface
3.3 V 4.7 K 3.3 V 4.7 K

100 nF PD14 3.3 V 4.7 K PD8 100 nF USART3_Tx USART3_Rx PE0 3.3 V 4.7 K 100 IrDA transceiver PE1 100 PD12

100 nF 3.3 V 100 4.7 K

100 nF

100

STM32F10xxx
100

100 nF

ai14352

15/23

STM32F10xxx USART IrDA mode

AN2582 - Application note

10.1.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. Five pins are used to select the byte to be sent. Each pressed key transmits an associated byte on the USART3_Tx pin These bytes are:

0x00 if no key pressed 0x01 if PD12 pin state changes 0x02 if PE0 pin state changes 0x03 if PE1 pin state changes 0x04 if PD8 pin state changes 0x05 if PD14 pin state changes

This firmware is provided as USART example 10 Transmit in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

10.1.4

Conclusion
The STM32F10xxx USART IrDA mode can be used to transmit data at the maximum baudrate of 115200 bps in accordance with the IrDA standard. The USART also supports the IrDA low-power mode.

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AN2582 - Application note

STM32F10xxx USART IrDA mode

10.2
10.2.1

STM32F10xxx USART IrDA Receive mode
Overview
This section describes how to build a basic communication with USART3 in IrDA Receive mode.

10.2.2

Hardware description
Figure 11 shows the STM32F10xxx IrDA interface. Figure 11. STM32F10xxx USART IrDA interface
PC6 600 PC7 600 PC8 IrDA transceiver USART3_Tx USART3_Rx PC9 600 600

STM32F10xxx
ai14353

10.2.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. The USART is waiting for a byte and depending on which byte is received, an LED will toggle. Four LEDs are used to indicate which byte is received.

when 0x04 is received the LED connected to PC6 toggles when 0x05 is received the LED connected to PC7 toggles when 0x03 is received the LED connected to PC8 toggles when 0x02 is received the LED connected to PC9 toggles when 0x01 is received the LEDs connected to PC6, PC7, PC8 and PC9 toggle

This firmware is provided as USART example 10 Receive in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

10.2.4

Conclusion
The STM32F10xxx USART IrDA mode can be used to receive data at the maximum baudrate of 115200 bps in accordance with the IrDA standard. The USART also supports the IrDA low-power mode.

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STM32F10xxx USART multiprocessor communication

AN2582 - Application note

11

STM32F10xxx USART multiprocessor communication
Overview
This section provides a description of how to use the USART in multiprocessor mode.

11.1

11.2

Hardware description
Figure 12 shows a typical interface between the STM32F10xxx USART1 and USART2. The USART1 signals (Rx, Tx) must be connected to a DB9 connector using an RS232 transceiver and the same connection must be done for the USART2 signals. Moreover, a null-modem female/female RS232 cable is connected between the two DB9 connectors (CN6 and CN5 on STM3210B-EVAL board). Figure 12. STM32F10xxx USART-USART interface
3.3 V 4.7 K

PC6 100 nF PB9 3.3 V 4.7 K USART1_RX PA0 100 nF USART2_TX USART2_RX 100 USART transceiver DB9 connector 100 USART1_TX USART transceiver DB9 connector 600

STM32F10xxx
ai14352

11.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, the USART1 and USART2 addresses are set to 0x1 and 0x2, respectively. USART1 continuously sends the 0x33 character to USART2. USART2 toggles an LED connected to the PC6 while receiving 0x33. When a falling edge is applied on EXTI Line9 (PB 9), an interrupt is generated and in the EXTI9_5_IRQ Handler routine, USART2 enters the mute mode and remains in this mode (no LED toggling) until a rising edge is applied on EXTI Line0 (PA0). In this interrupt routine, USART1 sends the address mark character (0x102) to wake up USART2. Then the LED restarts toggling. This firmware is provided as USART example 11 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

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AN2582 - Application note

STM32F10xxx USART multiprocessor communication

11.4

Conclusion
In multiprocessor configurations, it is often desirable that only the intended message recipient should actively receive the full message contents, thus reducing redundant USART service overhead for all non-addressed receivers.

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STM32F10x USART Smartcard mode

AN2582 - Application note

12
12.1

STM32F10x USART Smartcard mode
Overview
This section provides a description of how to use the USART in Smartcard mode. The example only gives the possibility to read the ATR (answer to reset) and decode it into a predefined buffer.

12.2

Hardware description
Figure 13 shows a typical interface between the STM32F10xxx and a Smartcard that supports the ISO 7816-3 character-oriented (T=0) protocol.

12.3

Firmware description
The provided firmware includes the USART driver that supports all USART communications through a set of functions. An example of use for most of these functions is provided. First, the code is waiting for a card insertion. If a card is detected through an EXTI Line interrupt, a reset signal is applied to the card through its reset pin. In response to this reset, the card transmits the ATR. Once received, the ATR is decoded and stored into a specific structure (SC_A2R). The card protocol type is stored into a variable. Then a test is performed to check if the inserted card is ISO 7816-3 T=0 compatible. This firmware is provided as USART example 12 in the STM32F10xxx firmware library, available from the STMicroelectronics microcontrollers website.

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AN2582 - Application note Figure 13. STM32F10x Smartcard interface

STM32F10x USART Smartcard mode

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Revision history

AN2582 - Application note

13

Revision history
Table 1.
Date 26-Jun-2007

Document revision history
Revision 1 Initial release. Changes

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AN2582 - Application note

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Document Number: 13661



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